The Mobile Airport Authority owns and operates the Mobile Downtown Airport, a public use airport located three miles south of the central business district of Mobile. The airport can trace its roots back to Brookley Field, a WWII era airfield. The airport is the principal component of the Mobile Aeroplex at Brookley, a 1,650-acre industrial complex. With the Mobile Airport, east coast to west coast rail lines, two Interstates I-65 (North/South) and I-10 (East/West), and the nearby Mobile Port Authority, the site is the perfect location for companies that engage in interstate commerce and aviation.
More than 75 companies lease space at Mobile Aeroplex, including FedEx, Signature Air Support, and VT Mobile Aerospace Engineering. Most recently, Airbus announced it would build its first North American final assembly line for the A320 family of jetliners at Brookley Aeroplex. As such, Mobile became the home of the company's first U.S.-based fixed wing aircraft production facility.
The continued growth of the Mobile Aeroplex necessitated the need for expansion of the airfield to make it compliant with new FAA standards and more operationally efficient. The expansion includes the construction of the partial parallel taxiway “A” relocation that will add about 3,500 linear feet to the taxiway.
Site drainage was a major challenge during the design phase of the taxiway project. With city stormwater runoff regulations restricting any increase in offsite flows from site-related drainage, planners had to review options carefully to ensure compliance with requirements and FAA advisory circulars when addressing drainage for the relocated parallel taxiway.
Detention ponds were not an option, as ponds attract waterfowl and other wildlife that are a safety hazard for aircraft. Therefore, engineers at Michael Baker Jr. Inc. designed 8 corrugated metal pipe detention systems using 20,770 linear feet of 60” diameter CORLIX aluminum pipe. Aluminum pipe was selected for this project due to its proximity to the Mobile Bay, which is a saline environment. The detention system stores stormwater underground and releases slowly over time into nearby Mobile Bay.
Thirteen VortSentry HS stormwater treatment systems were installed for pretreatment. The VortSentry HS units will prolong the life of the detention systems and reduces maintenance costs by removing sediment and retaining it in a structure that can be easily maintained.
Also used on the project was 680 LF of 48” ALT2 ULTRA FLO pipe for the purposes of sliplining some existing 54” RCP that experienced settlement problems at the joints. The entire 680 LF had to be pushed upstream from the outlet end due to airfield safety issues which prevented access into the upstream junction box structure.
Contech partnered with Alabama Pipe & Supply/Universal Precast to provide solutions for this project. Installation was completed in phases by H O Weaver & Sons in the fall of 2014 through the winter of 2016.